1. Field of the Invention
The present invention relates to image processing apparatuses and image processing methods for forming images.
2. Description of the Related Art
If a recording agent, such as toner, runs out or the amount of the recording agent becomes too insufficient to perform printing, in many cases printing is continued without the recording agent or is aborted to prompt the user to replenish the recording agent. In such a case, printing is often continued without the recording agent for ink-jet printing apparatuses, whereas printing is often aborted for electrophotographic printing apparatuses.
If printing is continued without the recording agent, that is, if printing is continued without a particular color, the subsequent images have colors or gray levels differing greatly from those intended. On the other hand, aborting printing prematurely is problematic especially while, for example, many sheets are being printed out from the printing apparatus after the user has issued a printing command.
To solve these problems, Japanese Patent Laid-Open No. 10-258530 proposes that if a particular recording agent runs out during printing, printing be continued with the recording agent of a different color. If, for example, light cyan (LC) ink or light cyan (LC) toner runs out during printing in a six-color printer that uses toners or inks of light cyan (LC) and light magenta (LM) in addition to yellow (Y), magenta (M), cyan (C), and black (K), then the C ink or C toner is used in place for the LC ink or LC toner that has run out. Furthermore, if the K ink or K toner runs out during printing, the C, M, and Y inks or C, M, and Y toners are used instead.
However, substituting a recording agent for another recording agent during printing to continue printing may cause the image quality of the print image, such as the tint and density, to differ between before and after the recording agent is substituted. In particular, when many copies of a single image are to be printed out, a change in image quality between before and after substitution of a recording agent can easily be recognized.